From e3d379a1ebf63a48f57a58d4f25fb85f83d57fed Mon Sep 17 00:00:00 2001
From: Wertzui123 <46199283+Wertzui123@users.noreply.github.com>
Date: Thu, 30 Sep 2021 08:32:20 +0200
Subject: [PATCH] builtin: add byte.repeat() and rune.repeat() (#12007)

---
 vlib/builtin/int.v       | 22 ++++++++++++++++++++++
 vlib/builtin/int_test.v  |  7 +++++++
 vlib/builtin/rune.v      | 14 ++++++++++++++
 vlib/builtin/rune_test.v | 13 +++++++++++++
 4 files changed, 56 insertions(+)
 create mode 100644 vlib/builtin/rune_test.v

diff --git a/vlib/builtin/int.v b/vlib/builtin/int.v
index 87594e90e429ed..00a44820a28cfb 100644
--- a/vlib/builtin/int.v
+++ b/vlib/builtin/int.v
@@ -507,3 +507,25 @@ pub fn (b []byte) bytestr() string {
 		return tos(buf, b.len)
 	}
 }
+
+// repeat returns a new string with `count` number of copies of the byte it was called on.
+pub fn (b byte) repeat(count int) string {
+	if count < 0 {
+		panic('byte.repeat: count is negative: $count')
+	} else if count == 0 {
+		return ''
+	} else if count == 1 {
+		return b.ascii_str()
+	}
+	mut ret := unsafe { malloc_noscan(count + 1) }
+	for i in 0 .. count {
+		unsafe {
+			ret[i] = b
+		}
+	}
+	new_len := count
+	unsafe {
+		ret[new_len] = 0
+	}
+	return unsafe { ret.vstring_with_len(new_len) }
+}
diff --git a/vlib/builtin/int_test.v b/vlib/builtin/int_test.v
index 3f233f1ebb74d7..17976685a12aaf 100644
--- a/vlib/builtin/int_test.v
+++ b/vlib/builtin/int_test.v
@@ -239,3 +239,10 @@ fn test_int_to_hex() {
 	assert i64(-1).hex() == 'ffffffffffffffff'
 	assert u64(18446744073709551615).hex() == 'ffffffffffffffff'
 }
+
+fn test_repeat() {
+	b := byte(`V`)
+	assert b.repeat(5) == 'VVVVV'
+	assert b.repeat(1) == b.ascii_str()
+	assert b.repeat(0) == ''
+}
diff --git a/vlib/builtin/rune.v b/vlib/builtin/rune.v
index 806010c3019b7c..d08f1f6f3015b0 100644
--- a/vlib/builtin/rune.v
+++ b/vlib/builtin/rune.v
@@ -39,3 +39,17 @@ pub fn (ra []rune) string() string {
 	unsafe { sb.free() }
 	return res
 }
+
+// repeat returns a new string with `count` number of copies of the rune it was called on.
+pub fn (c rune) repeat(count int) string {
+	if count < 0 {
+		panic('rune.repeat: count is negative: $count')
+	} else if count == 0 {
+		return ''
+	} else if count == 1 {
+		return c.str()
+	}
+	mut buffer := [5]byte{}
+	res := unsafe { utf32_to_str_no_malloc(u32(c), &buffer[0]) }
+	return res.repeat(count)
+}
diff --git a/vlib/builtin/rune_test.v b/vlib/builtin/rune_test.v
new file mode 100644
index 00000000000000..6b7e98786fbfb1
--- /dev/null
+++ b/vlib/builtin/rune_test.v
@@ -0,0 +1,13 @@
+fn test_repeat() {
+	r1 := `V`
+	r2 := `👋`
+
+	assert r1.repeat(5) == 'VVVVV'
+	assert r2.repeat(5) == '👋👋👋👋👋'
+
+	assert r1.repeat(1) == r1.str()
+	assert r2.repeat(1) == r2.str()
+
+	assert r1.repeat(0) == ''
+	assert r2.repeat(0) == ''
+}